Electro-mechanical printer

ABSTRACT

A printing apparatus is provided comprising a plurality of laterally disposed type bars vertically arranged and translatably mounted on a rockable type-bar carrying frame in front of a platen. The type bars are parallel to each other and spaced apart along the length of the platen. A cyclically controlled, driven splined member is laterally disposed and transversely positioned in front of the rockable type-bar carrying frame and below the platen, spanning all of the type bars. On the opposite side of the type bars is a plurality of like number of electrically controlled armature levers, variably timed, for coupling selected ones of the type bars with the splined member thereby to raise the selected type bars into a printing position, following which a pair of cams is operable to tilt the rockable type-bar carrying frame toward the platen to cause the selected type bars to strike against printable material positioned therebetween.

United States Patent [191 Deleuze et a1.

[ ELECTRO-MECHANICAL PRINTER [75] Inventors: Bernard Deleuze, Boulogne;

Jean-Claude Ragot, Sevran, both of France [73] Assignee: Burroughs Corporation, Detroit,

Mich.

[22] Filed: June 13, 1973 [21] App]. N0.: 369,590

Related U.S. Application Data [63] Continuation of Ser. No. 151,002, June 8, 1971,

[451 Oct. 8, 1974 5/1972 Findlay l0l/93 C 8/1972 Paige 101/93 C 5 7 ABSTRACT A printing apparatus is provided comprising a plurality of laterally disposed type bars vertically arranged and translatably mounted on a rockable type-bar carrying frame in front of a platen. The type bars are parallel to each other and spaced apart along the length of the platen. A cyclically controlled, driven splined member is laterally disposed and transversely positioned in front of the rockable type-bar carrying frame and below the platen, spanning all of the type bars. On the opposite side of the type bars is a plurality of like number of electrically controlled armature levers, variably timed, for coupling selected ones of the type bars with the splined member thereby to raise the selected type bars into a printing position, following which a pair of cams is operable to tilt the rockable type-bar carrying frame toward the platen to cause the selected type bars to strike against printable material positioned therebetween.

12 Claims, 14 Drawing Figures PAIENTED v SREEF '4 0f 4 FIGJO REGISTER CONVERTER KEY BOARD HO COMPARATOR H2 COUNTER ELECTRO-MECHANICAL PRINTER This is a continuation, of application Ser. No. 151,002, filed June 8, 1971 and now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention generally relates to a printing appara tus and particularly to the selective control and positioning of type bars in readiness for striking a platen.

2. Prior Art Known type printing mechanisms of calculating and accounting machines commonly include a platen and a plurality of vertically arranged type bars, each type bar being provided with a plurality of integrally fixed and longitudinally positioned type characters. In these known printing mechanisms, complex means are generally employed for differentially advancing selected type bars to bring preselected type characters into printing position relative to the platen, and a plurality of individually biased hammers are usually provided to afford each of the selected and differentially advanced type bars with a separate and variably timed striking force against an inked ribbon interposed between the type bars and the document-carrying platen. Such type bar selection and differential advancing means have generally been characterized by a multiplicity of intricate mechanical linkages which are resiliently associated with the data input means and responsively associated with the machine cycling means, and characterized also by separately activated type bar aligning means for bringing and holding the differentially advanced type bars precisely in printing position. The plurality of individually biased hammers have also generally required complicated mechanical pre-tensioning and triggering means, as well as intricate and critically timed hammer releasing means. The effect of using this plurality of individually biased hammers has generally been a lack of uniform ink density as between the several orders of the printed result, such lack of uniformity arising by way of variations in the striking force of the selected type bars as activated by their associated and individually biased hammers.

SUMMARY It is accordingly an object of the present invention to provide an improved printing apparatus for use in calculating and accounting machines wherein the type bar selection and advancing means are separated, and wherein such separation results in the elimination of the usual intricate mechanical linkages and in consequence manufacturing economies resulting therefrom.

It is still another object of the invention to provide an improved printing apparatus wherein the type bar differential advancing means is characterized by a common positively driven rotating actuator, to thereby eliminate the need for separately activated type bar I viously used plurality of individually biased hammers and their pretensioning, triggering, and releasing means, to thereby afford uniformity of ink density as between the various orders of the printed result as well as manufacturing economies and improved performance and reliability as regards the embodying type printing mechanism.

An important aspect of the invention is the use of a rockable type-bar carrying frame into which the type bars of the printing apparatus are vertically and translatably mounted, the frame being rockable to impact the differentially advanced type bars against the inked ribbon and the document-bearing platen.

Another important aspect of the invention is the use of a driven splined member for differentially advancing selected type bars to printing position, such splined member being effective to produce varing degrees of advancement according to the pre-selected type characters to be printed.

Still another important aspect of the invention is provision of electrically controlled armature levers in cooperation with cyclical timing means and splined member coupling means disposed on each of the type bars, for coupling the selected type bars with the splined member at various predetermined times during the driven rotation of the splined member, such variable coupling serving to differentially advance the type bars according to the pre-selected characters to be printed.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantages of the invention will be more clearly understood from the following description when read in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a printing apparatus embodying features of the present invention;

FIG. 2 is a fragmentary vertical sectional view taken along line 22 of FIG. 1 and showing a type bar in its normal inactive position;

FIG. 2A is a fragmentary side elevation of the cams and sector arm and their corresponding positions with respect to the type bar as shown in FIG. 2;

FIG. 3 is a view similar to that of FIG. 2 and showing a type bar coupled with the splined member;

FIG. 3A is a view similar to that of FIG. 2A and corresponding with the position of the type bar as shown in FIG. 3;

FIG. 4 is a view similar to that of FIG. 3 and showing a type bar in the process of being advanced to printing position;

FIG. 4A is a view similar to that of FIG. 3A and corresponding with the position of the type bar as shown in FIG. 4;

FIG. 5 is a view similar to that of FIG. 4 and showing a type bar in the process of being impactably driven against the inked ribbon and document-bearing platen;

FIG. 5A is a view similar to that of FIG. 4A and corresponding with the position of the type bar as shown in FIG. 5;

FIG. 6 is a fragmentary side elevation, with parts removed for clarity, showing the type-characterrepresenting disk and electro-magnet comprising a pulse generator of the selective control means;

FIG. 7 is a partial left side elevation of a modified version of a type bar and connector member that may be used in the electro-mechanical printer, the connector member being located in its activated coupled positlon;

FIG. 8 is an end view of the type bar and connector member of FIG. 7, showing the arrangement of type characters and the forward portion of the interlocking feature;

FIG. 9 is a partial right side elevation of the modified version of FIG. 7, showing details of the interlocking feature of the connector member and type bar; and

FIG. 10 is a diagrammatic illustration of the electrical control apparatus effective for differentially advancing the type bars.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In a preferred embodiment of the invention, the printing apparatus provides for the selection and advancement of type carrying members or bars which are translatably mounted in a pivotally supported type-bar carrying frame. The frame is operatively associated with electrical control means having a time relationship with the controlled driven means for advancing selected ones of the type carrying members into impacting contact with the printable material. Referring to the drawings, there is shown a printing apparatus generally indicated at 10 having left and right side plates 12 and 14 respectively and further having a pair of parallel, horizontal support rods l6l6 fixed between the side plates 12 and 14. The side plates 12 and 14 carry three parallel shafts, 18, and 22 which are journaled in the side plates. Secured to the shaft 18 is a platen 24. On the shaft 20, there is fixed an elongated splined member 26 having eleven teeth thereon, and fixed to the shaft 22 there is a pair of identical cams 28-28 adjacent to the opposite ends thereof to rotate therewith. The shaft 20 extends through the left side plate 12 and has a pinion 30, fixed to its outer end which is operatively connected to an hereinafter described clutchcam assembly generally designated at 32 as shown in FIG. I. The clutch-cam assembly 32 receives its driving torque from a power source in the form of a drive motor 33 which is continuously operating and from which rotational motion is provided the shaft 22, a pair of cams 86 and 88, and the identical cams 28. The leftmost end of the shaft 22, as viewed in FIG. 1, is separated from the portion to which the cams 86, 88 and 28-28 are fixed, the leftmost end being rotated by a worm gear 35 fixed to a motor output shaft 41 and a gear 38 fixed to said leftmost end whenever the motor 33 is operating, and the shaft portion bearing the cams 86 and 88 and the identical cams 2828 being rotated by means of a well known one-revolution clutch designated 96 in Flg. I.

An important feature of the invention is the provision of a rockable type-bar or rack carrying frame generally indicated at 34 which is located between the side plates 12 and 14 and in a plane between and parallel to the shafts 20 and 22. Within the frame 34 there are a plurality of type-bars or racks arranged in the same plane as the frame 34. The lower end of the frame 34 is pivotally mounted on the side plates 12 and 14. An electrical control hosing 36 is laterally positioned with respect to the bottom portion of the rack carrying frame 34 and is fastened between the side plates 12 and 14. This housing contains electrical devices controlled from a pulse generator 39 having a disk 47 operative with an electro-magnet 49 as shown in FIG. 6. Electrical devices within the housing 36 are operatively associated with the individual type-bars as hereinafter fully explained.

The type-bar carrying frame 34 is positioned in front of the platen 24 and the splined member 26 and comprises a pair of spaced apart, parallel upright arms 40-40. Each arm 40, at its lower end, has a rearwardextended portion 42 forming an outwardly extending U-shaped mounting 43. The U-shaped mountings 43 are pivotally connected to a support shaft 44, fixed between the side plates, to allow the type-bar carrying frame 34 to be tilted toward and away from the platen 24. A roller 46 is journaled to the outer sides of the lower ends of the upright arms 40-40, each of the rollers 46 being held in contacting relationship with an associated one of the identical cams 28-28 by means of a pair of return springs 48 connected to the frame 34 and to suitable anchor means (not shown). Fixed to the upper ends of the arms 40-40 there is a comblike member 50 for guiding the upper portions of the type bars, and at approximately the midpoint of the arms 4040 and carried therebetween is a notched circular guide member 52 for supporting and guiding the intermediate portions of type bars 54. The members 50 and 52 accordingly serve to guide and to carry a plurality of the type bars 54 so that the bars are vertically and translatably mounted in the frame 34 as shown in FIGS. 1 through 5.

The type bars 54 are, in general, of a conventional and well known type, each having a plurality of different type print elements 55 disposed thereon. The number of type print elements 55 corresponds to a like number of teeth 57 disposed on the lower portion of the type bars 54. A lead weight 53, as best shown in FIGS. 2 through 5, is secured to the bottom of each of the type bars 54, which serves as a counter-mass to facilitate their printing impact against the platen 24. The type bars 54 are parallelly spaced apart along the length of the platen 24, and are further characterized by an upper longitudinally extending slot 56 and a lower similarly extending slot 56, as also best shown in FIGS. 2 through 5. The upper slot 56 opens out through the top end of the type bar and straddles the comb 50 to receive guidance therefrom. The lower slot 56 receives the circular notched guide member 52 for further support. The two slots of each type bar cooperate to provide the required vertical guidance of the type bar in the frame 34 during its differential advancement, as hereinafter fully explained.

The type bars 54 each carry a connector member 58 for coupling the type bar to the splined member 26, as to be advanced thereby. Each connector 58 has an upper offset portion 59 pivotally mounted as at 60 to the side surface of its associated type bar, and is pivotally biased away from the splined member 26 by a flexure member 61 acting against a pin 63 fixed to the type bar, the connector thereby normally assuming an inactive vertical position as shown in FIGS. 1 and 2. The connector member 58 is also provided with a lower offset portion 62 having a pair of teeth 64 dimensionally shaped to engage the individual teeth of the splined member 26. Between the offset portions 59 and 62 of each connector, there is a lobe 66 disposed operatively adjacent an associated elongated armature lever 68 of the electrical control housing 36. Each lever 68, when actuated, will strike the lobe 66 of its associated connector 58 to effect engagement of its teeth 64 with a tooth of the splined member 26, as shown in FIG. 3. As above mentioned, the teeth 64 of the connector 58 are normally spaced from and laterally positioned with respect to the splined member 26, such positioning being effectuated by the flexure member 611 and pin 63.

Each of the elongated armature levers 68 is secured to a common horizontally extending notched spring member 70 carried by a bracket 72 which is fastened by screws 74 to the housing 36. The teeth 71 of the spring member 70 are individually secured to the lower portions of the levers and function as pivotal resisting supports therefor as will be more fully described hereinafter. The housing 36 contains a plurality of electrical devices earlier mentioned herein and illustrated as solenoids 76. These solenoids 76 are individually disposed in alignment with corresponding type bars 54, and are staggered in two rows to conserve space, as shown in FIG. I. As shown in FIGS. 2 and 3, each solenoid 76 includes a core 78, the cores of the two rows converging so that, when actuated, they will operate in the same horizontal plane on the levers 68. Each armature lever 68 is sufficiently long to reach the lobe 66 of its associated connector 58, such that the connector will remain in engagement with a tooth of the splined member 26 until, during the differential advancement of the type bar, the teeth 64 of the connector clear the splined member 26. Accordingly, when the selected solenoids 76 are energized by means of signals received from an electronic source, by way of the pulse generator 39, the lower ends of the levers 68 are attracted by and displaced toward the selected solenoids 76. The spring member 76 is twisted by this action, with the result that the upper ends of the selected levers 68 are moved toward and caused to strike the lobes 66 of the respective connectors 58, thereby effecting the engagement of the corresponding teeth 64 with the splined member 26, the selected type bars 54 being raised to printing position as a consequence thereof. The downwardly directed teeth or serrations 71 of the spring member 70 accordingly act as pivotal mounting supports for the armature levers 68, functioning similarly to a torsion bar and yieldingly resisting the attraction of the solenoids. This twisting of the spring member 70 enables the levers 68 to return to their normal vertical position after the selected solenoids 76 are deactivated, such deactivation occurring after the splined member 26 has rotated sufficiently to cause the teeth 64 of the connectors 58 to clear the splined member 26. Moreover, when the teeth 64 of the connectors 58 are disengaged from the splined driving member 26, the flexure members 611 of the activated connectors 58 serve to return the connectors 58 to their normal inactive positions, as best shown in FIGS. 2, 4 and 5.

The rockable frame 34 and the splined member 26 are operated from a common source of power, such as the motor 33, and, as earlier described herein, the motor operates through a clutch-cam assembly 32 by means of the worm gear 35, the gear 38, and the onerevolution clutch 96. The operating connection from the drive motor to the splined member 26 and to the frame 34 is such that during one cycle of operation frame 34 is rocked toward the platen 24 and returned,

' andthe splined member 26 is first rotated in one direction and then in the other so as to effectively raise and lower the selected type bars to and from their printing positions.

In the illustrated embodiment of the invention, the pinion 30 on the outer end of the shaft 20 engages a plurality of teeth 82 of a sector arm 84, the latter arm, as shown in FIGS. 2A5A, being so shaped and disposed as to partially surround the shaft 22 upon which the frame controlling pair of cams 28 as well as the cams 86 and 88 are mounted. The sector arm is pivotally mounted by a pin 90 on the outer side of the machine side plate ]l2, and spaced from the plate 12 by a collar 92. The sector arm 84 exhibits an approximately V-shaped formation from its pivotal axis, the V-shaped portions carrying cam follower rollers 94 and 95 on opposite sides thereof and positioned an equal distance from the pivotal axis 90 such as to operatively span the cam 86 and the countercam 88.

The cams 86 and 88 are eccentrically secured to the cam shaft 22 and are laterally spaced apart from one another to receive the sector arm 84 therebetween, thereby enabling the roller 94 to project outwardly from the arm to engage its respective cam 86, and the roller 95 to project inwardly to align with its respective countercam 88. The peripheral outline of the cams 86 and 88 are slightly out of circular shape, each having a smooth outwardly extending lobe as opposed to a relatively abrupt step or dwell. The cams 86 and 88 act through the rollers 94 and 95 during each operating cycle, to rock the sector arm 84 in an initial clockwise and an ensuing counterclockwise direction, to thereby alternately raise and lower the sector arm 84 and its arcuate row of teeth 82 and to accordingly drive the shaft 28 and the splined member 26 in a first counterclockwise direction and then in a second clockwise direction, such directions being defined as viewed in FIG. 1.

The sector arm operating earns 86 and 88, as previously indicated, are cooperatively associated with a well known one-revolution clutch shown at 96 in FIG. I, which is secured to the rightmost portion of the split shaft 22 and effective for coupling the rightmost cambearing portion of the shaft with the constantly rotating leftmost portion thereof. As is well known in the art, coupling of a one-revolution clutch generally involves the engagement of a clutch dog pivotally mounted on a disk fixed to the driven shaft (as would be contained in the clutch 96) with a toothed notch of the constantly rotating driving shaft, as designated at 100, upon ener gization of a solenoid or the like, such as the solenoid 98. Upon completing one complete revolution of the driven shaft, the clutch dog is disengaged from the toothed notch of the constantly rotating driving shaft,

the driven shaft remaining immobile until a succeeding cycle is initiated. In the instant embodiment of a printing device, coupling of the cam-bearing driven shaft 22 with the leftmost constantly rotating portion thereof will serve to rotate the cam-bearing portion one complete revolution, the cams 28-28 being effective to rock the frame 34 toward and away from the platen 24, and the cams 86 and 88 being effective to rotate the splined member 26 in an initial counterclockwise and an ensuing clockwise direction. The high points or lobes of the cams 86 and 88 are relatively closely angularly related as shown in FIGS. 2A-5A and cooperate to form a short dwell period following maximum rotation of the splined member 26 in a counterclockwise direction, such maximum rotation of the splined member being effective to raise the selected type bars to their respective printing positions according to the characters to be printed. It is during this dwell period that the lobes 102-102 of the two frame rocking cams 28-28 act on the rollers 46-46 to rock the frame 34 toward the platen to print the line of characters. The lobes 102-102 also complete their task during the dwell period, following which the springs 4848 return the frame 34 to its normal upright portion.

It is a significant chracteristic of the present invention that the rotation of the splined member 26 is begun immediately following entry of the amount to be printed, and that selected ones of the plurality of type bars 54 are coupled with the splined member 26 at various times during the latter members predetermined rotation, to thereby utilize appropriate varying degrees of the splined members rotation to differentially advance the selected type bars and to bring the desired type characters into printing position. As previously stated, each type bar 54 is provided with a connector member 58 cooperably associated with a separate armature lever 68 of the electrical control housing 36, each armature lever 68 being also operably associated with a separate solenoid 76 in the control housing. Each solenoid 76 is effective, upon energization, to pivot its associated armature lever 68 and to rotate its associated connector member 58 into engagement with a tooth of the splined member 26. This engagement of a connector member 58 with a tooth of the rotating splined member 26 serves to initiate the differential advancement of the corresponding type bar 54. Electrical control means, generally illustrated in FIG. 10, are accordingly provided to the end that the solenoids 76 associated with the various selected type bars 54 might be energized at the appropriate time during the predetermined rotation of the splined member 26. As indicated at 104 in FIG. 10, suitable data input means such as a well known lO-key keyboard may be used for entering an amount to be printed by the electro-mechanical printer, such amount being entered in decimal form and transmitted along the line 104 to a converter 106 where it is converted to binary form. A decimal to binary converter suitable for this purpose is disclosed in U. S. Pat. No. 3,652,826 which issued on Mar. 28, 1972, such patent being assigned to the assignee of the present invention. The binary data representing the entered amount is thereupon transferred along the line 106 to a register 107 where it is stored, as for example by means of suitable bistable elements such as flipflops. The binary data stored in the register 107 is coupled to a comparator 110 as indicated by the line 107, the comparator being comprised of suitable triggering elements such as an array of AND gates effective for receiving inputs from both the bistable elements of the register 107 and from a counter 112. The register 107 and the comparator 110 may be comprised of a separate group of elements for each of the type bars 54, the register 107, for example, providing a separate group of four bistable elements for each of the type bars, and the comparator 110 providing a separate array of AND gates for each of the type bars, each group of bistable elements of the register representing the decimalbi'nary values 1, 2, 4 and 8, and each array of AND gates of the comparator 110 being operably associated with a corresponding group of bistable elements of the register 107.

As the splined member 26 is rotated in a counterclockwise direction (as viewed in FIG. a disk 47 attached to the rightmost extremity of the shaft 22 is also rotated in a counterclockwise direction, to thereby bring a plurality of projections disposed along its periphery into cooperating relationship with an electromagnet 49. As each of these disk projections is brought into cooperating relationship with the electro-magnet, the pulse generator, generally designated at 39, produces a pulse that is transmitted along the line 49 to the counter 112, the counter in turn serving to transmit a pulse to each of the type-bar-representing arrays of AND gates of the comparator along the line 112'.

As illustrated in FIG. 10, the first disk projection to be brought into cooperating relationship with the electro-magnet 49 represents the decimal point character of the various type bars, and the remaining 10 disk projections represent the type characters 9, 8, 7, 6, 5, 4, 3, 2, l, and 0, respectively, of the various type bars. As illustrated in FIG. 8, the arrangement of type characters on the individual type bars is such that the decimal point is located in the lowermost position, and the type characters 9 through 0 are located in declining order thereabove with the zero type character located in the uppermost position. It will be apparent from the illustration of FIG. 8 that a maximum advancement of a type bar will be required to bring its decimal point type character into printing position, and a minimum advancement will be required to bring its zero type character into printing position. The effect of the control apparatus of FIG. 10 is accordingly to couple those type bars 54 that are to print decimal points early in the counterclockwise rotation of the splined member 26 and as the decimal-point-representing disk projection moves into operationg relationship with the electromagnet 49, and to couple those type bars that are to print zeros late in the splined members rotation as the zero-representing disk projection moves into cooperating relationship with the electro-magnet 49. The type bars that are to print from 9 through 1 are coupled at appropriate intervening times in the rotation of the splined member, as their respective type-characterrepresenting disk projections are moved into operating relationship with the electro-magnet. This variable coupling of the type bars 54, according to the type characters to be printed thereby, is accomplished by gating output pulses from the comparator 110 along the line 110 to the appropriate solenoids 76 whenever a matching comparison is made between the pulses generated by the character-representing projections of the disk 47 and the amount or information stored in the register 107.

A modification of the connector members 58 shown in FIGS. 1 through 6 is illustrated in FIGS. 7 through 9, such modification being designed to provide positive limits for the connector members when in their coupled and uncoupled positions, and to provide an interlocking relationship between each connector member and its associated type bar. The modified connector member 58 is provided with a vertical offset portion 118, as best shown in FIG. 9, which is held in limiting contact with a cutout portion of the type bar 54 by the flexure member 61, when the connector member is located in its inactive, uncoupled position. An offset portion 126 is also formed on the lobe 66, such offset portion being brought into limiting contact with the surface area 128 of the type bar when the connector member is activated to its coupled position with a tooth of the splined member 26. In addition to the cutout portion 120, the type bar 54 shown in FIG. 9 is also provided with a substantially square aperture 115, said aperture being provided in its upper-right corner (as viewed in FIG. 9) with a reduced web portion 116 that is flush with the side surface of the type bar adjacent the connector member 58, the reduced portion being disposed opposite said side surface. The modified connector member 58 is provided with an offset web portion 114 contiguous to the mounting stud 60, which is also disposed on the connector member, this offset web portion of the connector member serving to retainably engage the reduced web portion 116 of the type bar when the connector member and type bar are asembled together by means of the mounting stud 60. The modified connector member 58 is also held in interlocked relationship with the type bar 54 by means of an upright extension 122 formed on the vertical offset portion 118 of the connector member, such upright extension slidably and retainably cooperating with a reduced web portion 124 formed in the cutout 120 of the type bar. The web portion 124 is flush with the side surface of the type bar adjacent the connector member 58, and the reduced portion thereof is slidably and cooperably engageable by the upright extension 122 of the connector member.

The offset web portion 114 and the upright extension 122 of the modified connector member 58 together with the reduced web portions 116 and 124 of the modified type bar 54 are so disposed as to facilitate the assembly of the connecotr members 58 on their associated type bars 54. This assembly is accomplished by first inserting the offset web portion 114 of the connector member into and through the square aperture 115 of the type bar such that the offset web portion 114 engages the reduced portion of the web 116, and by then rotating the connector member in such manner as to bring the mounting stud 60 into engaged relationship with its associated hole in the type bar, the connector member 58 being then rotated an additional distance with its offset portion 126 held clear of the surface area 128 of the type bar, to a point where the upright extension 122 of the vertical offset portion 118 of the connector member clears the reduced web portion 124 formed in the cutout 120 of the type bar. Upon the occurrence of such clearance, the connector member is rotated a minimal distance in the opposite direction until its offset portion 126 engageably clears the surface area 128 of the type bar. Upon the occurrence of such clearance, the connector member is retainably and interlockably mounted for activation into and out of coupling relationship with the splined member 26.

In addition to the previously mentioned characteristics of the type bars 54 of the preferred embodiment of the present invention, the upper open-ended slot 56 of each type bar 54 serves to present a bifurcated portion comprising a pair of forked members of different length, the shorter member thereof carrying on its outer edge the longitudinally arranged printing type 55, and the longer member thereof carrying the pivotally mounted connector member 58, as shown in FIGS. 1 through 5. The length of the shorter forked member of each type bar 54 is so dimensioned as to provide clearance of the comb-like member 50 thereabove when the type bar is located in its inactive home position, and as to be received by a corresponding recess of the comblike member 50 when the type bar is located in a differentially advanced position. The length of the longer forked member of each type bar 54, on the other hand, is so dimensioned as to remain in contactable relationship with the comb-like member 50 regardless of whether the type bar is located in. its home position or in a differentially advanced position. The effect of this described dimensioning of the shorter and longer forked members of the bifurcated portion of each type bar 54 is that those type bars which have been translatably and differentially advanced to printing position will be impactably rocked into printing contact with the platen by the comb-like member 50 of the rockable frame 34, and that those type bars that remain in their translatory home positions will be retained in their upright rockable home positions during the impactable rocking of the comb-like member 50 and the rockable frame 34, such home positioned type bars receiving guidable support from their corresponding notchesor circumferential grooves of the cylindrical guide member 52 during the interval of rockable angular displacement of the comb-like member 51).

OPERATION To operate the preferred embodiment of this electromechanical printer, power to the constant running drive motor 33 is first turned on through any suitable means such as a switch. With the power on, the drive motor 33, the drive shaft 41 and worm gear 35 thereof, the gear 38 and the leftmost separated portion of the shaft 22 continue to rotate preparatory to the entry and printing of amounts. An amount to be printed may be entered through any suitable input means such as a keyboard generally represented at 104 in FIG. 10, such entry resulting in the conversion of the amount by means of the converter 106 and the storage of corresponding binary values in the register 107. A suitable operation control key or motor bar of the keyboard is then depressed, whereupon the electro-magnet or solenoid 93 is energized to activate the well known one revolution clutch 96 shown in FIG. 1. The onerevolution clutch effectively couples the rightmost cam-bearing portion of the shaft 22 with its separated leftmost rotating portion, to thereby rotate the rightmost portion of the shaft one complete revolution. As the rightmost portion of the shaft rotates, the cams 86 and 68 attached thereto are rotate-d to effectively pivot the sector arm 84 in a clockwise direction on its axis 90, by means of the rollers 94 and 95. The arcuate row of teeth 82 of the sector arm 84 accordingly serve to rotate the pinion 30, the shaft 20, and the splined member 26 in a counterclockwise direction (as viewed in FIG. 1). As the shaft 20 is rotated, the type-characterrepresenting disk 47 attached to the rightmost extremity thereof is rotated in a counterctockwise direction to bring the various type-character-representing projections thereof into cooperating relationship with the electro-magnet 49 (FIG. 10). Each of the disk projections successively serves to transmit a pulse along the line 49 to the counter 112, and to the various AND gates of the comparator along the line 112'. Those AND gates of the comparator 110 which receive inputs from both the counter 112 and the register 107 thereupon transmit pulses along the line 110' to the solenoids 76 corresponding to the type bars that are to print the type character represented by the disk projection 47 that is located in cooperating relationship with the electro-magnet 49. As the solenoids 76 are ener gized, their corresponding armature levers 68 are pivoted on the spring member 70 to thereby activate the associated connector members 58 into coupled relationship with the teeth of the rotating splined member 26. The various type bars 54 are thereupon differentially advanced to printing position, such position being represented by the maximum counterclockwise rotation of the shaft and splined member 26 when the cams 86 and 88 are disposed in their previously described dwell period. During the differential advancement of the type bars 54, the armature levers 68 are restored to their upright inactive positions by the spring member 70, upon de-energization of the solenoids 76, such de-energization occuring as the type-characterrepresenting projections of the disk 47 are moved out of cooperating relationship with the electro-magnet 49. During the differential advancement of the type bars 54, the coupled connector members 58 are also restored to their inactive uncoupled positions by their individual flexure members 61, as their individual lobes 66 are elevated to a cleared position relative to the uppermost extremities of their armature levers 68, such restoration occuring after the uppermost teeth 57 of the type bars 54 are engaged with the splined member Following the maximum predetermined counterclockwise rotation of the splined member 26, the high points or lobes 102-102 of the twin cams 28-28 fixed to the rotating shaft 22 are effective to activate the rollers 4646 to rock the frame 34 in a counterclockwise direction on the support shaft 44, to thereby impact the differentially advanced type bars into printable contact with the ribbon and printable material carried by the platen 24. As the lobes 102-102 are withdrawn from the rollers 4646, the frame 34 is restored to its upright home position by the springs 48 connected to the upright arms 40-40. The differentially advanced type bars 54 are then returnably lowered to their home positions by the predetermined return rotation of the pinion 30, the shaft 20 and the splined member 26, such return rotation being motivated by the action of the cams 86 and 88 on the sector arm 84. Upon completion of the one revolution rotation of the rightmost cambearing portion of the shaft 22, the well known onerevolution clutch 96 is effective to uncouple said rightmost portion from the leftmost rotating portion thereof, the latter portion continuing to rotate independently of the cambearing portion until a succeeding printing operation is indexed.

While an embodiment of the invention has been shown and described in considerable detail, it will be apparent that other adaptations and modifications may be made by one skilled in the art without departing from the true spirit and scope of the invention.

What is claimed is:

1. Printing apparatus having input means, motive means, a plurality of laterally disposed and vertically arranged type bars each carrying printing type spaced apart longitudinally thereof, and a platen transversely disposed of said type bars, said printing apparatus being characterized by:

a. a rockable frame for translatably carrying said plurality of type bars,

b. actuatable means responsive to said input means and said motive means for vertically translating said type bars within said rockable frame to bring the printing type thereof into printing position relative to said platen,

c. a connector member pivotally mounted on each of said type bars,

(1. means for individually coupling said connector members of said type bars with said translating means before or during the actuation of said translating means to thereby bring selected printing type thereof into printing position, and

e. means responsive to said motive means effective for impactably rocking said frame and said selected printing type of said type bars into printable contact with said platen, said rocking means comprising a first rotatable shaft, a one revolution clutch effective for coupling said first shaft with said motive means for one complete revolution therewith, and a first pair of cams fixed to said first shaft and effective for impactably rocking said frame and said type bars at a predetermined point during said complete revolution of said first shaft.

2. The printing apparatus defined in claim 1 wherein said means for vertically translating said type bars to bring the printing type thereof into printing position comprises:

a. a splined member operatively associated with said plurality of type bars and particularly with the connector members thereof, and

b. splined member activating means associated with said motive means and with said first rotatable shaft of said frame rocking means.

3. The printing apparatus defined in claim 2 wherein said splined member is comprised of a plurality of engageable toothed formations that transversely span all of said type bars, said splined member being disposed in parallel relationship with said type bars and said rockable frame.

4. The printing apparatus defined in claim 3 wherein said splined member activating means comprises:

a. a second rotatable shaft disposed on the opposite side of said rockable frame from said first rotatable shaft, said second rotatable shaft providing rigid support for said splined member,

b. a pinion fixed to said second rotatable shaft in spaced relationship from said splined member,

c. a second pair of cams fixed to said first rotatable shaft, and

d. a pivotally mounted sector arm disposed in cooperating relationship with said second pair of cams and with said pinion, said sector arm being effective to rotate said pinion, said second rotatable shaft and said splined member a predetermined advancing and return distance during each complete revolution of said first rotatable shaft.

5. The printing apparatus defined in claim 3 wherein each of said connector members of said type bars is provided on one edge thereof with a lobe portion and on the opposite edge with a pair of teeth, and wherein said means for individually coupling said connector members with said translating means comprises electrical control means responsive to said input means and effective for contacting said lobe portions of said connector members before or during said actuation of said splined member of said translating means to thereby engage said pairs of teeth of said connector members with said toothed formations of said splined member.

6. The printing apparatus defined in claim 5 wherein said electrical control means responsive to said input means and effective for engaging said teeth of said connector members with said toothed formations of said splined member comprises:

a. a plurality of electrically operated devices individually and operatively associated with said connector members of said type bars to effectuate coupling as between said type bars and said splined member, said plurality of devices being activatable selectively in timed relation to the rotation of the splined member to effectively and differentially advance said type bars, and

b. electrical operating means responsive to said input means and effective for selectively activating said plurality of electrically operated devices in said timed relation to the rotation of the splined member to thereby advance said selected printing type into printing position relative to said platen.

7. The printing apparatus defined in claim 6 wherein each of said plurality of electrically operated devices comprises:

a. a resiliently pivotal armature lever associated with a corresonding one of said connector members pivotally mounted on said type bars, and

b. a solenoid operatively associated with each of said resiliently pivotal armature levers and responsive to said electrical operating means to pivot said resiliently pivotal armature lever to effectively couple said associated connector member with one of said toothed formations of said splined member.

8. The printing apparatus defined in claim 6 wherein said electrical operating means is responsive to said input means and comprises:

a. a decimal to binary converter whereby an amount to be printed is converted from decimal to binary form,

b. a register wherein binary information representing an amount to be printed is stored,

c. a pulse generator associated with said splined member and responsive to said predetermined advancing rotation thereof to generate a predetermined series of pulses representing said printing type spaced apart longitudinally on each of said type bars, and

d. a pulse triggering comparator associated with said register and with said pulse generator effective for triggering pulses to corresponding ones of said electrically operated devices when a matching comparison is made between said register and said comparator, said triggering of pulses serving to identify the type bars that are to print the printing type represented by individual ones of said series of pulses generated by said pulse generator, and to couple said identified type bars with said splined member in timed relationship with said advancing rotation thereof.

9. In printing apparatus having input means, motive means, a plurality of laterally disposed and vertically arranged type bars each carrying printing type spaced apart longitudinally thereof, and a platen transversely disposed of said type bars, the improvement comprising: a rockable type-bar-supporting frame including a pair of pivotally mounted upright arms, a comb-like recessed member connecting said pair of upright arms and disposed in parallel contiguous relationship to said platen, and a circumferentially grooved cylindrical guide member connecting said pair of upright arms at a point intermediate said comb-like member and said pivotal mounting thereof; electrically controlled type bar translating means including an actuatable splined member and a plurality of connector members pivotally mounted on said type bars and couplable with said splined member; and electrically controlled impactable rocking means effective for impactably rocking said type-bar-supporting frame, said electrically controlled translating means and impactable rocking means being effective in combination and in response to said input means and said motive means to differentially advance selected ones of said type bars to bring selected printing type into printing position relative to said platen, and to impactably rock said selected type bars into printing contact with said platen to thereby effectuate printing by means of said selected printing type.

10. The printing apparatus defined in claim 9' wherein each of said type bars additionally comprises:

a. a lower closed slot for guidably receiving a corresponding one of the circumferential grooves of said cylindrical guide member,

b. an upper open-ended slot for receiving a corresponding one of the recesses formed in said comblike member during its differential translation,

c. a weighted lower extremity contributing to the impacting force with which it is rocked by said typebar-supporting frame into printing contact with said platen.

11. The printing apparatus defined in claim 10 wherein the uppermost extremity of each type bar presents a bifurcated portion formed by said upper openended slot, said bifurcated portion comprising a pair of forked members of different length, the shorter forked member carrying on the outer edge thereof said longitudinally arranged printing type, said shorter forked member being disposed in cleared and non-contacting relationship with said comb-like member when said type bar is located in its inactive home position, and being received by a corresponding recess formed in said comb-like member when said type bar is located in a differentially advanced position.

12. The printing apparatus defined in claim 11 wherein by means of said bifurcated portions of said type bars and said shorter members thereof, those selected type bars that are differentially advanced by said electrically controlled type bar translating means to bring selected printing type into printing position are impactably rocked into printing contact with said platen by said comb-like member when activated by said electrically controlled impactable rocking means, and those type bars that remain in their inactive home positions remain in an upright unrocked position dur ing the rockable and angular displacement of said comb-like member, said home-positioned type bars during said angular displacement of said comb-like member being supportably retained by said rockable type-bar supporting frame by means of said circumferentially grooved cylindrical guide member. 

1. Printing apparatus having input means, motive means, a plurality of laterally disposed and vertically arranged type bars each carrying printing type spaced apart longitudinally thereof, and a platen transversely disposed of said type bars, said printing apparatus being characterized by: a. a rockable frame for translatably carrying said plurality of type bars, b. actuatable means responsive to said input means and said motive means for vertically translating said type bars within said rockable frame to bring the printing type thereof into printing position relative to said platen, c. a connector member pivotally mounted on each of said type bars, d. means for individually coupling said connector members of said type bars with said translating means before or during the actuation of said translating means to thereby bring selected printing type thereof into printing position, and e. means responsive to said motive means effectIve for impactably rocking said frame and said selected printing type of said type bars into printable contact with said platen, said rocking means comprising a first rotatable shaft, a one revolution clutch effective for coupling said first shaft with said motive means for one complete revolution therewith, and a first pair of cams fixed to said first shaft and effective for impactably rocking said frame and said type bars at a predetermined point during said complete revolution of said first shaft.
 2. The printing apparatus defined in claim 1 wherein said means for vertically translating said type bars to bring the printing type thereof into printing position comprises: a. a splined member operatively associated with said plurality of type bars and particularly with the connector members thereof, and b. splined member activating means associated with said motive means and with said first rotatable shaft of said frame rocking means.
 3. The printing apparatus defined in claim 2 wherein said splined member is comprised of a plurality of engageable toothed formations that transversely span all of said type bars, said splined member being disposed in parallel relationship with said type bars and said rockable frame.
 4. The printing apparatus defined in claim 3 wherein said splined member activating means comprises: a. a second rotatable shaft disposed on the opposite side of said rockable frame from said first rotatable shaft, said second rotatable shaft providing rigid support for said splined member, b. a pinion fixed to said second rotatable shaft in spaced relationship from said splined member, c. a second pair of cams fixed to said first rotatable shaft, and d. a pivotally mounted sector arm disposed in cooperating relationship with said second pair of cams and with said pinion, said sector arm being effective to rotate said pinion, said second rotatable shaft and said splined member a predetermined advancing and return distance during each complete revolution of said first rotatable shaft.
 5. The printing apparatus defined in claim 3 wherein each of said connector members of said type bars is provided on one edge thereof with a lobe portion and on the opposite edge with a pair of teeth, and wherein said means for individually coupling said connector members with said translating means comprises electrical control means responsive to said input means and effective for contacting said lobe portions of said connector members before or during said actuation of said splined member of said translating means to thereby engage said pairs of teeth of said connector members with said toothed formations of said splined member.
 6. The printing apparatus defined in claim 5 wherein said electrical control means responsive to said input means and effective for engaging said teeth of said connector members with said toothed formations of said splined member comprises: a. a plurality of electrically operated devices individually and operatively associated with said connector members of said type bars to effectuate coupling as between said type bars and said splined member, said plurality of devices being activatable selectively in timed relation to the rotation of the splined member to effectively and differentially advance said type bars, and b. electrical operating means responsive to said input means and effective for selectively activating said plurality of electrically operated devices in said timed relation to the rotation of the splined member to thereby advance said selected printing type into printing position relative to said platen.
 7. The printing apparatus defined in claim 6 wherein each of said plurality of electrically operated devices comprises: a. a resiliently pivotal armature lever associated with a corresonding one of said connector members pivotally mounted on said type bars, and b. a solenoid operatively associated with each of said resiliently pivotal armature levers and responsIve to said electrical operating means to pivot said resiliently pivotal armature lever to effectively couple said associated connector member with one of said toothed formations of said splined member.
 8. The printing apparatus defined in claim 6 wherein said electrical operating means is responsive to said input means and comprises: a. a decimal to binary converter whereby an amount to be printed is converted from decimal to binary form, b. a register wherein binary information representing an amount to be printed is stored, c. a pulse generator associated with said splined member and responsive to said predetermined advancing rotation thereof to generate a predetermined series of pulses representing said printing type spaced apart longitudinally on each of said type bars, and d. a pulse triggering comparator associated with said register and with said pulse generator effective for triggering pulses to corresponding ones of said electrically operated devices when a matching comparison is made between said register and said comparator, said triggering of pulses serving to identify the type bars that are to print the printing type represented by individual ones of said series of pulses generated by said pulse generator, and to couple said identified type bars with said splined member in timed relationship with said advancing rotation thereof.
 9. In printing apparatus having input means, motive means, a plurality of laterally disposed and vertically arranged type bars each carrying printing type spaced apart longitudinally thereof, and a platen transversely disposed of said type bars, the improvement comprising: a rockable type-bar-supporting frame including a pair of pivotally mounted upright arms, a comb-like recessed member connecting said pair of upright arms and disposed in parallel contiguous relationship to said platen, and a circumferentially grooved cylindrical guide member connecting said pair of upright arms at a point intermediate said comb-like member and said pivotal mounting thereof; electrically controlled type bar translating means including an actuatable splined member and a plurality of connector members pivotally mounted on said type bars and couplable with said splined member; and electrically controlled impactable rocking means effective for impactably rocking said type-bar-supporting frame, said electrically controlled translating means and impactable rocking means being effective in combination and in response to said input means and said motive means to differentially advance selected ones of said type bars to bring selected printing type into printing position relative to said platen, and to impactably rock said selected type bars into printing contact with said platen to thereby effectuate printing by means of said selected printing type.
 10. The printing apparatus defined in claim 9 wherein each of said type bars additionally comprises: a. a lower closed slot for guidably receiving a corresponding one of the circumferential grooves of said cylindrical guide member, b. an upper open-ended slot for receiving a corresponding one of the recesses formed in said comb-like member during its differential translation, c. a weighted lower extremity contributing to the impacting force with which it is rocked by said type-bar-supporting frame into printing contact with said platen.
 11. The printing apparatus defined in claim 10 wherein the uppermost extremity of each type bar presents a bifurcated portion formed by said upper open-ended slot, said bifurcated portion comprising a pair of forked members of different length, the shorter forked member carrying on the outer edge thereof said longitudinally arranged printing type, said shorter forked member being disposed in cleared and non-contacting relationship with said comb-like member when said type bar is located in its inactive home position, and being received by a corresponding recess formed in said comb-like member when said type bar is located in a diFferentially advanced position.
 12. The printing apparatus defined in claim 11 wherein by means of said bifurcated portions of said type bars and said shorter members thereof, those selected type bars that are differentially advanced by said electrically controlled type bar translating means to bring selected printing type into printing position are impactably rocked into printing contact with said platen by said comb-like member when activated by said electrically controlled impactable rocking means, and those type bars that remain in their inactive home positions remain in an upright unrocked position during the rockable and angular displacement of said comb-like member, said home-positioned type bars during said angular displacement of said comb-like member being supportably retained by said rockable type-bar supporting frame by means of said circumferentially grooved cylindrical guide member. 